Austrian Patent No. 369 660 (corresponds to U.S. Pat. No. 4,428,597) describes a heel holder for a safety ski binding, in particular a safety ski binding convertible between a cross-country and a downhill mode of skiing. The heel holder has a bearing block which can be fixed relative to the ski and a housing which has a down-holding means and which can be swung up against the force of a spring. The spring is arranged in a spring chamber provided in the housing and has one end supported on a housing-fixed part and the other end on an adjustable abutment supported on the bearing block. The abutment is pivotal about an axis which is arranged on the bearing block. The axis--viewed in longitudinal direction of the ski--is offset upwardly and to the rear with respect to the control bolt. A control bolt is mounted on the housing and is guided along a cam surface arranged on each of the two sidewalls of the bearing block. Further, each cam is defined by the inner edge of a kidney-shaped or arcuate recess located in each sidewall of the bearing block. The two end regions of both recesses, figuratively speaking, "point" in a direction toward the ski shoe.
This heel holder has proved to be very successful due to its realiable designa and experiences great popularity. However, in the case of a voluntary release of the heel holder, the release lever always had to be pivoted and necessitated a compressing of the spring stored in the spring chamber. The ability of the ski shoe to leave the heel holder in emergency situations without effecting a pivoting of the release lever did not exist in the known construction.
The goal of the invention is to overcome this disadvantage and to provide an improvement to the known heel holder such that the possibility of an emergency exiting from the binding is possible and without necessitating an operation of a release lever.
This goal is inventively achieved primarily by the projecting ends of an axle being supported in slide rings guided in arcuate grooves, the center points of which, in the skiing position of the heel holder, coincide with the axis of the control bolt, are guided on the inner sides of the sidewalls of the bearing block and can be locked in their uppermost position. When the two slide rings are unlocked, they can slide downwardly and the ski shoe can leave the heel holder.
Various possibilities exist for the structural features of the lock for the two slide rings. Thus, according to a first embodiment of the locking device for the slide rings in the upper position, a U-shaped bar is provided, the legs of which are guided in grooves arranged on the inner sides of the sidewalls, extend radially with respect to the control bolt and intersect the circular grooves for the slide rings. It is preferable for the bar to be under the influence of at least one spring which urges it to move into the locking position.
Another inventive embodiment is distinguished by swingably supporting a U-shaped lever on the inner sides of the sidewalls of the bearing block, the lever arms thereof having projections on its free ends, which projections, in the skiing position, secure the two slide rings against movement in the grooves. In this design it is preferable for the lever to be under the influence of at least one spring urging it into a position wherein its projections project into the grooves and path of movement for the slide rings.